Composition and method for preventing or reducing low speed pre-ignition in direct injected spark-ignited engines

ABSTRACT

Disclosed is a lubricating engine oil composition comprising a lubricating oil base stock as a major component, and at least one metal or metalloid hydrogen atom donor compound. Also disclosed is a method for preventing or reducing low speed pre-ignition in a direct injected, boosted, spark ignited internal combustion engine, and the use of at least one metal or metalloid hydrogen atom donor compound in a lubricating engine oil composition for preventing or reducing low speed pre-ignition in a direct injected, boosted, spark ignited internal combustion engine.

FIELD OF THE INVENTION

This disclosure relates to a lubricant composition that contains atleast one metal hydride compound. The disclosure also relates to alubricant composition that contains at least one metal or metalloidhydrogen atom donor compound for a direct injected, boosted, sparkignited internal combustion engine. This disclosure also relates to amethod for preventing or reducing low speed pre-ignition in an enginelubricated with a formulated oil. The formulated oil has a compositioncomprising at least one oil soluble or oil dispersible metal ormetalloid hydrogen atom donor compound.

BACKGROUND OF THE INVENTION

In recent years, engine manufacturers have developed smaller (downsized)engines which provide higher power densities and excellent performancewhile reducing frictional and pumping losses. This is accomplished byincreasing boost pressures with the use of turbochargers or mechanicalsuperchargers, and by down-speeding the engine by using highertransmission gear ratios allowed by higher torque generation at lowerengine speeds. However, higher torque at lower engine speeds has beenfound to cause random pre-ignition in engines at low speeds, aphenomenon known as Low Speed Pre-Ignition, or LSPI, resulting inextremely high cylinder peak pressures, which can lead to catastrophicengine failure. The possibility of LSPI prevents engine manufacturersfrom fully optimizing engine torque at lower engine speed in suchsmaller, high-output engines.

One of the leading theories surrounding the cause of low speedpre-ignition (LSPI) is at least in part, due to auto-ignition of engineoil droplets that enter the engine combustion chamber from the pistoncrevice under high pressure, during periods in which the engine isoperating at low speeds, and compression stroke time is longest (Amannet al. SAE 2012-01-1140).

Although some engine knocking and pre-ignition problems can be and arebeing resolved through the use of new engine technology, such aselectronic controls and knock sensors, and through the optimization ofengine operating conditions, there is a need for lubricating oilcompositions which can decrease or prevent the LSPI problem, and alsoimprove or maintain other performance such as wear and oxidationprotection.

The present inventors have discovered a solution for addressing theproblem of LSPI through the use of a metal hydride compound.

SUMMARY OF THE INVENTION

Disclosed is a lubricating engine oil composition for use in down-sizedboosted engines comprising a lubricating oil base stock as a majorcomponent, one or more silicon hydrides, germanium hydrides, and tinhydrides as minor component; wherein the downsized engine ranges from0.5 liters to 3.6 liters.

Also disclosed is a method for preventing or reducing low speedpre-ignition in a direct injected, boosted, spark ignited internalcombustion engine, said method comprising the step of lubricating thecrankcase of the engine with a lubricating oil composition comprisingfrom about 25 to about 3000 ppm of a metal or metalloid from the metalor metalloid hydrogen atom donor from one or more silicon hydrides,germanium hydrides, and tin hydrides, based on the total weight of thelubricating oil composition.

Further disclosed is the use of one or more silicon hydrides, germaniumhydrides, and tin hydrides in a lubricating engine oil composition forpreventing or reducing low speed pre-ignition in a direct injected,boosted, spark ignited internal combustion engine.

DETAILED DESCRIPTION OF THE INVENTION

The term “boosting” is used throughout the specification. Boostingrefers to running an engine at higher intake pressures than in naturallyaspirated engines. A boosted condition can be reached by use of aturbocharger (driven by exhaust) or a supercharger (driven by theengine). “Boosting” allow engine manufacturers to use smaller engines,which provide higher power densities, to provide excellent performancewhile reducing frictional and pumping losses.

Throughout the specification and claims the expression oil soluble ordispersible is used. By oil soluble or dispersible is meant that anamount needed to provide the desired level of activity or performancecan be incorporated by being dissolved, dispersed or suspended in an oilof lubricating viscosity. Usually, this means that at least about 0.001%by weight of the material can be incorporated in a lubricating oilcomposition. For a further discussion of the terms oil soluble anddispersible, particularly “stably dispersible”, see U.S. Pat. No.4,320,019 which is expressly incorporated herein by reference forrelevant teachings in this regard.

The term “sulfated ash” as used herein refers to the non-combustibleresidue resulting from detergents and metallic additives in lubricatingoil. Sulfated ash may be determined using ASTM Test D874.

The term “Total Base Number” or “TBN” as used herein refers to theamount of base equivalent to milligrams of KOH in one gram of sample.Thus, higher TBN numbers reflect more alkaline products, and therefore agreater alkalinity. TBN was determined using ASTM D 2896 test.

Unless otherwise specified, all percentages are in weight percent.

In general, the level of sulfur in the lubricating oil compositions ofthe present invention is less than or equal to about 0.7 wt. %, based onthe total weight of the lubricating oil composition, e.g., a level ofsulfur of about 0.01 wt. % to about 0.70 wt. %, 0.01 to 0.6 wt.%, 0.01to 0.5 wt.%, 0.01 to 0.4 wt.%, 0.01 to 0.3 wt.%, 0.01 to 0.2 wt.%, 0.01wt. % to 0.10 wt. %. In one embodiment, the level of sulfur in thelubricating oil compositions of the present invention is less than orequal to about 0.60 wt. %, less than or equal to about 0.50 wt. %, lessthan or equal to about 0.40 wt. %, less than or equal to about 0.30 wt.%, less than or equal to about 0.20 wt. %, less than or equal to about0.10 wt. % based on the total weight of the lubricating oil composition.

In one embodiment, the levels of phosphorus in the lubricating oilcompositions of the present invention is less than or equal to about0.12 wt. %, based on the total weight of the lubricating oilcomposition, e.g., a level of phosphorus of about 0.01 wt. % to about0.12 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.11 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.11 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.10 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.10 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.09 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.09 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.08 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.08 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.07 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.07 wt. %. In one embodiment, the levels of phosphorus in thelubricating oil compositions of the present invention is less than orequal to about 0.05 wt. %, based on the total weight of the lubricatingoil composition, e.g., a level of phosphorus of about 0.01 wt. % toabout 0.05 wt. %.

In one embodiment, the level of sulfated ash produced by the lubricatingoil compositions of the present invention is less than or equal to about1.60 wt. % as determined by ASTM D 874, e.g., a level of sulfated ash offrom about 0.10 to about 1.60 wt. % as determined by ASTM D 874. In oneembodiment, the level of sulfated ash produced by the lubricating oilcompositions of the present invention is less than or equal to about1.00 wt. % as determined by ASTM D 874, e.g., a level of sulfated ash offrom about 0.10 to about 1.00 wt. % as determined by ASTM D 874. In oneembodiment, the level of sulfated ash produced by the lubricating oilcompositions of the present invention is less than or equal to about0.80 wt. % as determined by ASTM D 874, e.g., a level of sulfated ash offrom about 0.10 to about 0.80 wt. % as determined by ASTM D 874. In oneembodiment, the level of sulfated ash produced by the lubricating oilcompositions of the present invention is less than or equal to about0.60 wt. % as determined by ASTM D 874, e.g., a level of sulfated ash offrom about 0.10 to about 0.60 wt. % as determined by ASTM D 874.

Suitably, the present lubricating oil composition may have a total basenumber (TBN) of 4 to 15 mg KOH/g (e.g., 5 to 12 mg KOH/g, 6 to 12 mgKOH/g, or 8 to 12 mg KOH/g).

Low Speed Pre-Ignition is most likely to occur in direct-injected,boosted (turbocharged or supercharged), spark-ignited (gasoline)internal combustion engines that, in operation, generate a break meaneffective pressure level of greater than about 15 bar (peak torque),such as at least about 18 bar, particularly at least about 20 bar atengine speeds of from about 1500 to about 2500 rotations per minute(rpm), such as at engine speeds of from about 1500 to about 2000 rpm. Asused herein, break mean effective pressure (BMEP) is defined as the workaccomplished during one engine cycle, divided by the engine sweptvolume; the engine torque normalized by engine displacement. The word“brake” denotes the actual torque/power available at the engineflywheel, as measured on a dynamometer. Thus, BMEP is a measure of theuseful power output of the engine.

In one embodiment of the invention, the engine is operated at speedsbetween 500 rpm and 3000 rpm, or 800 rpm to 2800 rpm, or even 1000 rpmto 2600 rpm. Additionally, the engine may be operated with a break meaneffective pressure of 10 bars to 30 bars, or 12 bars to 24 bars.

LSPI events, while comparatively uncommon, may be catastrophic innature. Hence drastic reduction or even elimination of LSPI eventsduring normal or sustained operation of a direct fuel injection engineis desirable. In one embodiment, the method of the invention is suchthat there are less than 150 LSPI events/million combustion cycles (canalso be expressed as 15 LSPI events/100,000 combustion cycles) or lessthan 100 LSPI events/million combustion cycles or less than 70 LSPIevents/million combustion cycles or less than 60 LSPI events/millioncombustion cycles or less than 50 LSPI events/million combustion cyclesor less than 40 LSPI events/million combustion cycles, less than 30 LSPIevents/million combustion cycles, less than 20 LSPI events/millioncombustion cycles, less than 10 LSPI events/million combustion cycles,or there may be 0 LSPI events/million combustion cycles.

Therefore, in an aspect the present disclosure provides a method forpreventing or reducing low speed pre-ignition in a direct injected,boosted, spark ignited internal combustion engine, said methodcomprising the step of lubricating the crankcase of the engine with alubricating oil composition comprising at least one metal hydridecompound. In one embodiment, the amount of metal from the at least onemetal hydride is from about 100 to about 3000 ppm, from about 200 toabout 3000 ppm, from about 250 to about 2500 ppm, from about 300 toabout 2500 ppm, from about 350 to about 2500 ppm, from about 400 ppm toabout 2500 ppm, from about 500 to about 2500 ppm, from about 600 toabout 2500 ppm, from about 700 to about 2500 ppm, from about 700 toabout 2000 ppm, from about 700 to about 1500 ppm in the lubricating oilcomposition. In one embodiment, the amount of metal from the metal ormetalloid hydrogen atom donor compounds is no more than about 2000 ppmor no more than 1500 ppm in the lubricating oil composition.

In one embodiment, the method of the invention provides a reduction inthe number of LSPI events of at least 10 percent, or at least 20percent, or at least 30 percent, or at least 50 percent, or at least 60percent, or at least 70 percent, or at least 80 percent, or at least 90percent, or at least 95 percent, compared to an oil that does notcontain the at least one metal hydride compound.

In another aspect, the present disclosure provides a method for reducingthe severity of low speed pre-ignition events in a direct injected,boosted, spark ignited internal combustion engine, said methodcomprising the step of lubricating the crankcase of the engine with alubricating oil composition comprising at least one metal hydridecompound. LSPI events are determined by monitoring peak cylinderpressure (PP) and the crank angle of 2% mass fraction burn (MFB02) ofthe fuel charge in the cylinder. When both criteria are met, it can besaid that an LSPI event has occurred. The threshold for peak cylinderpressure varies by test, but is typically 4-5 standard deviations abovethe average cylinder pressure. Likewise, the MFB02 crank angle thresholdis typically 4-5 standard deviations earlier than the average MFB02crank angle. LSPI events can be reported as average events per test,events per 100,000 combustion cycles, events per cycle, and/orcombustion cycles per event. In one embodiment, the number of LSPIevents, where both MFB02 and Peak Pressure (PP) Requirements that weregreater than 90 bar of pressure, is less than 15 events, less than 14events, less than 13 events, less than 12 events, less than 11 events,less than 10 events, less than 9 events, less than 8 events, less than 7events, less than 6 events, is less than 5 events, less than 4 events,less than 3 events, less than 2 events, or less than 1 event per 100,000combustion cycles. In one embodiment, the number of LSPI events thatwere greater than 90 bar was zero events, or in other words completelysuppressed LSPI events greater than 90 bar. In one embodiment, thenumber of LSPI events where both MFB02 and Peak Pressure (PP)Requirements that were greater than 100 bar of pressure is less than 15events, less than 14 events, less than 13 events, less than 12 events,less than 11 events, less than 10 events, less than 9 events, less than8 events, less than 7 events, less than 6 events, is less than 5 events,less than 4 events, less than 3 events, less than 2 events, or less than1 event per 100,000 combustion cycles. In one embodiment, the number ofLSPI events that were greater than 100 bar was zero events, or in otherwords completely suppressed LSPI events greater than 100 bar. In oneembodiment, the number of LSPI events where both MFB02 and Peak Pressure(PP) Requirements that were greater than 110 bar of pressure is lessthan 15 events, less than 14 events, less than 13 events, less than 12events, less than 11 events, less than 10 events, less than 9 events,less than 8 events, less than 7 events, less than 6 events, is less than5 events, less than 4 events, less than 3 events, less than 2 events, orless than 1 event per 100,000 combustion cycles In one embodiment, thenumber of LSPI events that were greater than 110 bar was zero events, orin other words completely suppressed LSPI events greater than 110 bar.For example, the number of LSPI events where both MFB02 and PeakPressure (PP) Requirements that were greater than 120 bar of pressure isless than 15 events, less than 14 events, less than 13 events, less than12 events, less than 11 events, less than 10 events, less than 9 events,less than 8 events, less than 7 events, less than 6 events, is less than5 events, less than 4 events, less than 3 events, less than 2 events, orless than 1 event per 100,000 combustion cycles. In one embodiment, thenumber of LSPI events that were greater than 120 bar was zero events, orin other words completely suppressed very severe LSPI events (i.e.,events greater than 120 bar).

It has now been found that the occurrence of LSPI in engines susceptibleto the occurrence of LSPI can be reduced by lubricating such engineswith lubricating oil compositions containing a metal hydride compound.

The disclosure further provides the method described herein in which theengine is fueled with a liquid hydrocarbon fuel, a liquid nonhydrocarbonfuel, or mixtures thereof.

Lubricating oil compositions suitable for use as passenger car motoroils conventionally comprise a major amount of oil of lubricatingviscosity and minor amounts of performance enhancing additives,including ash-containing compounds. Conveniently, the metals asdescribed herein are introduced into the lubricating oil compositionsused in the practice of the present disclosure by one or more metal ormetalloid hydrogen atom donor compounds.

Oil of Lubricating Viscosity/Base Oil Component

The oil of lubricating viscosity for use in the lubricating oilcompositions of this disclosure, also referred to as a base oil, istypically present in a major amount, e.g., an amount of greater than 50wt. %, preferably greater than about 70 wt. %, more preferably fromabout 80 to about 99.5 wt. % and most preferably from about 85 to about98 wt. %, based on the total weight of the composition. The expression“base oil” as used herein shall be understood to mean a base stock orblend of base stocks which is a lubricant component that is produced bya single manufacturer to the same specifications (independent of feedsource or manufacturer's location); that meets the same manufacturer'sspecification; and that is identified by a unique formula, productidentification number, or both. The base oil for use herein can be anypresently known or later-discovered oil of lubricating viscosity used informulating lubricating oil compositions for any and all suchapplications, e.g., engine oils, marine cylinder oils, functional fluidssuch as hydraulic oils, gear oils, transmission fluids, etc.Additionally, the base oils for use herein can optionally containviscosity index improvers, e.g., polymeric alkylmethacrylates; olefiniccopolymers, e.g., an ethylene-propylene copolymer or a styrene-dienecopolymer; and the like and mixtures thereof.

As one skilled in the art would readily appreciate, the viscosity of thebase oil is dependent upon the application. Accordingly, the viscosityof a base oil for use herein will ordinarily range from about 2 to about2000 centistokes (cSt) at 100° Centigrade (C.). Generally, individuallythe base oils used as engine oils will have a kinematic viscosity rangeat 100° C. of about 2 cSt to about 30 cSt, preferably about 3 cSt toabout 16 cSt, and most preferably about 4 cSt to about 12 cSt and willbe selected or blended depending on the desired end use and theadditives in the finished oil to give the desired grade of engine oil,e.g., a lubricating oil composition having an SAE Viscosity Grade of 0W,0W-4, 0W-8, 0W-12, 0W-16, 0W-20, 0W-26, 0W-30, 0W-40, 0W-50, 0W-60, 5W,5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50,15W, 15W-20, 15W-30, 15W-40, 30, 40 and the like.

Group I base oils generally refer to a petroleum derived lubricatingbase oil having a saturates content of less than 90 wt. % (as determinedby ASTM D 2007) and/or a total sulfur content of greater than 300 ppm(as determined by ASTM D 2622, ASTM D 4294, ASTM D 4297 or ASTM D 3120)and has a viscosity index (VI) of greater than or equal to 80 and lessthan 120 (as determined by ASTM D 2270).

Group II base oils generally refer to a petroleum derived lubricatingbase oil having a total sulfur content equal to or less than 300 partsper million (ppm) (as determined by ASTM D 2622, ASTM D 4294, ASTM D4927 or ASTM D 3120), a saturates content equal to or greater than 90weight percent (as determined by ASTM D 2007), and a viscosity index(VI) of between 80 and 120 (as determined by ASTM D 2270).

Group III base oils generally refer to a petroleum derived lubricatingbase oil having less than 300 ppm sulfur, a saturates content greaterthan 90 weight percent, and a VI of 120 or greater.

Group IV base oils are polyalphaolefins (PAOs).

Group V base oils include all other base oils not included in Group I,II, III, or IV.

The lubricating oil composition can contain minor amounts of other baseoil components. For example, the lubricating oil composition can containa minor amount of a base oil derived from natural lubricating oils,synthetic lubricating oils or mixtures thereof. Suitable base oilincludes base stocks obtained by isomerization of synthetic wax andslack wax, as well as hydrocracked base stocks produced by hydrocracking(rather than solvent extracting) the aromatic and polar components ofthe crude. Suitable natural oils include mineral lubricating oils suchas, for example, liquid petroleum oils, solvent-treated or acid-treatedmineral lubricating oils of the paraffinic, naphthenic or mixedparaffinic-naphthenic types, oils derived from coal or shale, animaloils, vegetable oils (e.g., rapeseed oils, castor oils and lard oil),and the like.

Suitable synthetic lubricating oils include, but are not limited to,hydrocarbon oils and halo-substituted hydrocarbon oils such aspolymerized and interpolymerized olefins, e.g., polybutylenes,polypropylenes, propylene-isobutylene copolymers, chlorinatedpolybutylenes, poly(1-hexenes), poly(1-octenes), poly(1-decenes), andthe like and mixtures thereof; alkylbenzenes such as dodecylbenzenes,tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)-benzenes, and thelike; polyphenyls such as biphenyls, terphenyls, alkylated polyphenyls,and the like; alkylated diphenyl ethers and alkylated diphenyl sulfidesand the derivative, analogs and homologs thereof and the like.

Other synthetic lubricating oils include, but are not limited to, oilsmade by polymerizing olefins of less than 5 carbon atoms such asethylene, propylene, butylenes, isobutene, pentene, and mixturesthereof. Methods of preparing such polymer oils are well known to thoseskilled in the art.

Additional synthetic hydrocarbon oils include liquid polymers of alphaolefins having the proper viscosity. Especially useful synthetichydrocarbon oils are the hydrogenated liquid oligomers of C₆ to C₁₂alpha olefins such as, for example, 1-decene trimer.

Another class of synthetic lubricating oils include, but are not limitedto, alkylene oxide polymers, i.e., homopolymers, interpolymers, andderivatives thereof where the terminal hydroxyl groups have beenmodified by, for example, esterification or etherification. These oilsare exemplified by the oils prepared through polymerization of ethyleneoxide or propylene oxide, the alkyl and phenyl ethers of thesepolyoxyalkylene polymers (e.g., methyl poly propylene glycol etherhaving an average molecular weight of 1,000, diphenyl ether ofpolyethylene glycol having a molecular weight of 500-1000, diethyl etherof polypropylene glycol having a molecular weight of 1,000-1,500, etc.)or mono- and polycarboxylic esters thereof such as, for example, theacetic esters, mixed C₃-C₈ fatty acid esters, or the C₁₃ oxo aciddiester of tetraethylene glycol.

Yet another class of synthetic lubricating oils include, but are notlimited to, the esters of dicarboxylic acids e.g., phthalic acid,succinic acid, alkyl succinic acids, alkenyl succinic acids, maleicacid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipicacid, linoleic acid dimer, malonic acids, alkyl malonic acids, alkenylmalonic acids, etc., with a variety of alcohols, e.g., butyl alcohol,hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol,diethylene glycol monoether, propylene glycol, etc. Specific examples ofthese esters include dibutyl adipate, di(2-ethylhexyl)sebacate,di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecylazelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the2-ethylhexyl diester of linoleic acid dimer, the complex ester formed byreacting one mole of sebacic acid with two moles of tetraethylene glycoland two moles of 2-ethylhexanoic acid and the like.

Esters useful as synthetic oils also include, but are not limited to,those made from carboxylic acids having from about 5 to about 12 carbonatoms with alcohols, e.g., methanol, ethanol, etc., polyols and polyolethers such as neopentyl glycol, trimethylol propane, pentaerythritol,dipentaerythritol, tripentaerythritol, and the like.

Silicon-based oils such as, for example, polyalkyl-, polyaryl-,polyalkoxy- or polyaryloxy-siloxane oils and silicate oils, compriseanother useful class of synthetic lubricating oils. Specific examples ofthese include, but are not limited to, tetraethyl silicate,tetra-isopropyl silicate, tetra-(2-ethylhexyl) silicate,tetra-(4-methyl-hexyl)silicate, tetra-(p-tert-butylphenyl)silicate,hexyl-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes,poly(methylphenyl)siloxanes, and the like. Still yet other usefulsynthetic lubricating oils include, but are not limited to, liquidesters of phosphorous containing acids, e.g., tricresyl phosphate,trioctyl phosphate, diethyl ester of decane phosphionic acid, etc.,polymeric tetrahydrofurans and the like.

The lubricating oil may be derived from unrefined, refined and rerefinedoils, either natural, synthetic or mixtures of two or more of any ofthese of the type disclosed hereinabove. Unrefined oils are thoseobtained directly from a natural or synthetic source (e.g., coal, shale,or tar sands bitumen) without further purification or treatment.Examples of unrefined oils include, but are not limited to, a shale oilobtained directly from retorting operations, a petroleum oil obtaineddirectly from distillation or an ester oil obtained directly from anesterification process, each of which is then used without furthertreatment. Refined oils are similar to the unrefined oils except theyhave been further treated in one or more purification steps to improveone or more properties. These purification techniques are known to thoseof skill in the art and include, for example, solvent extractions,secondary distillation, acid or base extraction, filtration,percolation, hydrotreating, dewaxing, etc. Rerefined oils are obtainedby treating used oils in processes similar to those used to obtainrefined oils. Such rerefined oils are also known as reclaimed orreprocessed oils and often are additionally processed by techniquesdirected to removal of spent additives and oil breakdown products.

Lubricating oil base stocks derived from the hydroisomerization of waxmay also be used, either alone or in combination with the aforesaidnatural and/or synthetic base stocks. Such wax isomerate oil is producedby the hydroisomerization of natural or synthetic waxes or mixturesthereof over a hydroisomerization catalyst.

Natural waxes are typically the slack waxes recovered by the solventdewaxing of mineral oils; synthetic waxes are typically the wax producedby the Fischer-Tropsch process. Other useful fluids of lubricatingviscosity include non-conventional or unconventional base stocks thathave been processed, preferably catalytically, or synthesized to providehigh performance lubrication characteristics.

Metal or Metalloid Hydrogen Atom Donor Compounds The lubrication oilcompositions herein can contain one or more metal or metalloid hydrogenatom donor compounds selected from the group consisting of siliconhydrides, germanium hydrides, and tin hydrides.

In one aspect, the one or more metal or metalloid hydrogen atom donorcompounds have the following formula:

where R₁, R₂, and R₃ are each independently selected from hydrogen atom,a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, aC3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₁, R₂, and R₃ are a hydrogen atom; R₄ isa C₆-C₁₄ aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R7 is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and M is asilicon atom, germanium atom, or tin atom.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where R₂ and R₃ are each independently selected from a C6-C14 arylgroup, alkyl group, or a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆,—O(═O)R₇, or chlorine atom, R₄ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₅ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₆ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₇ is aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group; and M is a silicon atom, germanium atom, or tinatom.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where R₁, R₂, and R₃ are each independently selected from hydrogen atom,a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, aC3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₁, R₂, and R₃ are a hydrogen atom; R₄ isa C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where R₂ and R₃ are each independently selected from hydrogen atom, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, a C3-C10cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom, R₄ is aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where R₁, R₂, and R₃ are each independently selected from hydrogen atom,a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, aC3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₂, and R₃ are a hydrogen atom; R₄ is aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where R₁, R₂, and R₃ are each independently selected from hydrogen atom,a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, aC3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₂, and R₃ are a hydrogen atom; R₄ is aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where is R₈₆ is a C6-C14 aryl group, saturated or unsaturated C1-C30alkyl group, or a C3-C10 cycloalkyl group; and n is 0 or an integer from1 to 400.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

where n is 0 or an integer from 1 to 400.

In one embodiment, the one or more metal or metalloid hydrogen atomdonor compounds have the following formula:

wherein R₉ is a C6-C14 aryl group, saturated or unsaturated C1-C30 alkylgroup; and m is an integer from 1 to 20.

In one embodiment, the metal or metalloid hydrogen atom donor compoundis one in which the hydride is directly bonded to the metal atom. In oneembodiment, the metal hydride is not a silazane.

Generally, the amount of the metal or metalloid hydrogen atom donorcompound can be from about 0.001 wt. % to about 25 wt. %, from about0.05 wt. % to about 20 wt. %, or from about 0.1 wt. % to about 15 wt. %,or from about 0.1 wt. % to about 5 wt. %, from about, 0.1 wt. % to about4.0 wt. %, based on the total weight of the lubricating oil composition.

In an aspect, the present disclosure provides a lubricating engine oilcomposition for a direct injected, boosted, spark ignited internalcombustion engine comprising at least one metal hydride compound. In oneembodiment, the amount of metal from the at least one metal or metalloidhydrogen atom donor compound is from about 25 to about 3000 ppm, fromabout 100 to about 3000 ppm, from about 200 to about 3000 ppm, or fromabout 250 to about 2500 ppm, from about 300 to about 2500 ppm, fromabout 350 to about 2500 ppm, from about 400 ppm to about 2500 ppm, fromabout 500 to about 2500 ppm, from about 600 to about 2500 ppm, fromabout 700 to about 2500 ppm, from about 700 to about 2000 ppm, fromabout 700 to about 1500 ppm. In one embodiment, the amount of metal fromthe metal or metalloid hydrogen atom donor compound is no more thanabout 2000 ppm or no more than about 1500 ppm. The metals in each ofthese embodiments being selected from silicon, germanium, tin or acombination thereof.

In one embodiment, the metal or metalloid hydrogen atom donor compoundscan be combined with conventional lubricating oil detergent additiveswhich contain magnesium and/or calcium. In one embodiment the calciumdetergent(s) can be added in an amount sufficient to provide thelubricating oil composition from 0 to about 2400 ppm of calcium metal,from 0 to about 2200 ppm of calcium metal, from 100 to about 2000 ppm ofcalcium metal, from 200 to about 1800 ppm of calcium metal, or fromabout 100 to about 1800 ppm, or from about 200 to about 1500 ppm, orfrom about 300 to about 1400 ppm, or from about 400 to about 1400 ppm,of calcium metal in the lubricating oil composition. In one embodimentthe magnesium detergent(s) can be added in an amount sufficient toprovide the lubricating oil composition from about 100 to about 1000 ppmof magnesium metal, or from about 100 to about 600 ppm, or from about100 to about 500 ppm, or from about 200 to about 500 ppm of magnesiummetal in the lubricating oil composition.

In one embodiment, the metal or metalloid hydrogen atom donor compoundscan be combined with conventional lubricating oil detergent additiveswhich contain lithium. In one embodiment the lithium detergent(s) can beadded in an amount sufficient to provide the lubricating oil compositionfrom 0 to about 2400 ppm of lithium metal, from 0 to about 2200 ppm oflithium metal, from 100 to about 2000 ppm of lithium metal, from 200 toabout 1800 ppm of lithium metal, or from about 100 to about 1800 ppm, orfrom about 200 to about 1500 ppm, or from about 300 to about 1400 ppm,or from about 400 to about 1400 ppm, of lithium metal in the lubricatingoil composition.

In one embodiment, the metal or metalloid hydrogen atom donor compoundscan be combined with conventional lubricating oil detergent additiveswhich contain sodium. In one embodiment the sodium detergent(s) can beadded in an amount sufficient to provide the lubricating oil compositionfrom 0 to about 2400 ppm of sodium metal, from 0 to about 2200 ppm ofsodium metal, from 100 to about 2000 ppm of sodium metal, from 200 toabout 1800 ppm of sodium metal, or from about 100 to about 1800 ppm, orfrom about 200 to about 1500 ppm, or from about 300 to about 1400 ppm,or from about 400 to about 1400 ppm, of sodium metal in the lubricatingoil composition.

In one embodiment, the metal or metalloid hydrogen atom donor compoundcan be combined with conventional lubricating oil detergent additiveswhich contain potassium. In one embodiment the potassium detergent(s)can be added in an amount sufficient to provide the lubricating oilcomposition from 0 to about 2400 ppm of potassium metal, from 0 to about2200 ppm of potassium metal, from 100 to about 2000 ppm of potassiummetal, from 200 to about 1800 ppm of potassium metal, or from about 100to about 1800 ppm, or from about 200 to about 1500 ppm, or from about300 to about 1400 ppm, or from about 400 to about 1400 ppm, of potassiummetal in the lubricating oil composition.

In one embodiment, the disclosure provides a lubricating engine oilcomposition comprising a lubricating oil base stock as a majorcomponent; and at least one metal hydride compound, as a minorcomponent; and wherein the engine exhibits greater than 50% reduced lowspeed pre-ignition, based on normalized low speed pre-ignition (LSPI)counts per 100,000 engine cycles, engine operation at between 500 and3,000 revolutions per minute and brake mean effective pressure (BMEP)between 10 and 30 bar, as compared to low speed pre-ignition performanceachieved in an engine using a lubricating oil that does not comprise ofat least one metal hydride compound.

In one aspect, the disclosure provides a lubricating engine oilcomposition for use in a down-sized boosted engine comprising alubricating oil base stock as a major component; and at least one metalhydride compound, as a minor component; where the downsized engineranges from about 0.5 to about 3.6 liters, from about 0.5 to about 3.0liters, from about 0.8 to about 3.0 liters, from about 0.5 to about 2.0liters, or from about 1.0 to about 2.0 liters. The engine can have two,three, four, five or six cylinders.

In an aspect, the present disclosure provides the use of a at least onemetal or metalloid hydrogen atom donor compound for preventing orreducing low speed pre-ignition in a direct injected, boosted, sparkignited internal combustion engine.

Lubricating Oil Additives

In addition to the metal or metalloid hydrogen atom donor compoundsdescribed herein, the lubricating oil composition can compriseadditional lubricating oil additives.

The lubricating oil compositions of the present disclosure may alsocontain other conventional additives that can impart or improve anydesirable property of the lubricating oil composition in which theseadditives are dispersed or dissolved. Any additive known to a person ofordinary skill in the art may be used in the lubricating oilcompositions disclosed herein. Some suitable additives have beendescribed in Mortier et al., “Chemistry and Technology of Lubricants,”2nd Edition, London, Springer, (1996); and Leslie R. Rudnick, “LubricantAdditives: Chemistry and Applications,” New York, Marcel Dekker (2003),both of which are incorporated herein by reference. For example, thelubricating oil compositions can be blended with antioxidants, anti-wearagents, metal detergents, rust inhibitors, dehazing agents, demulsifyingagents, metal deactivating agents, friction modifiers, pour pointdepressants, antifoaming agents, co-solvents, corrosion-inhibitors,ashless dispersants, multifunctional agents, dyes, extreme pressureagents and the like and mixtures thereof. A variety of the additives areknown and commercially available. These additives, or their analogouscompounds, can be employed for the preparation of the lubricating oilcompositions of the disclosure by the usual blending procedures.

The lubricating oil composition of the present invention can contain oneor more detergents. Metal-containing or ash-forming detergents functionas both detergents to reduce or remove deposits and as acid neutralizersor rust inhibitors, thereby reducing wear and corrosion and extendingengine life. Detergents generally comprise a polar head with a longhydrophobic tail. The polar head comprises a metal salt of an acidicorganic compound. The salts may contain a substantially stoichiometricamount of the metal in which case they are usually described as normalor neutral salts. A large amount of a metal base may be incorporated byreacting excess metal compound (e.g., an oxide or hydroxide) with anacidic gas (e.g., carbon dioxide).

Detergents that may be used include oil-soluble neutral and overbasedsulfonates, phenates, sulfurized phenates, thiophosphonates,salicylates, and naphthenates and other oil-soluble carboxylates of ametal, particularly the alkali or alkaline earth metals, e.g., barium,sodium, potassium, lithium, calcium, and magnesium. The most commonlyused metals are calcium and magnesium, which may both be present indetergents used in a lubricant, and mixtures of calcium and/or magnesiumwith sodium.

The lubricating oil composition of the present invention can contain oneor more anti-wear agents that can reduce friction and excessive wear.Any anti-wear agent known by a person of ordinary skill in the art maybe used in the lubricating oil composition. Non-limiting examples ofsuitable anti-wear agents include zinc dithiophosphate, metal (e.g., Pb,Sb, Mo and the like) salts of dithiophosphates, metal (e.g., Zn, Pb, Sb,Mo and the like) salts of dithiocarbamates, metal (e.g., Zn, Pb, Sb andthe like) salts of fatty acids, boron compounds, phosphate esters,phosphite esters, amine salts of phosphoric acid esters orthiophosphoric acid esters, reaction products of dicyclopentadiene andthiophosphoric acids and combinations thereof. The amount of theanti-wear agent may vary from about 0.01 wt. % to about 5 wt. %, fromabout 0.05 wt. % to about 3 wt. %, or from about 0.1 wt. % to about 1wt. %, based on the total weight of the lubricating oil composition.

In certain embodiments, the anti-wear agent is or comprises adihydrocarbyl dithiophosphate metal salt, such as zinc dialkyldithiophosphate compounds. The metal of the dihydrocarbyldithiophosphate metal salt may be an alkali or alkaline earth metal, oraluminum, lead, tin, molybdenum, manganese, nickel or copper. In someembodiments, the metal is zinc. In other embodiments, the alkyl group ofthe dihydrocarbyl dithiophosphate metal salt has from about 3 to about22 carbon atoms, from about 3 to about 18 carbon atoms, from about 3 toabout 12 carbon atoms, or from about 3 to about 8 carbon atoms. Infurther embodiments, the alkyl group is linear or branched.

The amount of the dihydrocarbyl dithiophosphate metal salt including thezinc dialkyl dithiophosphate salts in the lubricating oil compositiondisclosed herein is measured by its phosphorus content. In someembodiments, the phosphorus content of the lubricating oil compositiondisclosed herein is from about 0.01 wt. % to about 0.14 wt. %, based onthe total weight of the lubricating oil composition.

The lubricating oil composition of the present invention can contain oneor more friction modifiers that can lower the friction between movingparts. Any friction modifier known by a person of ordinary skill in theart may be used in the lubricating oil composition. Non-limitingexamples of suitable friction modifiers include fatty carboxylic acids;derivatives (e.g., alcohol, esters, borated esters, amides, metal saltsand the like) of fatty carboxylic acid; mono-, di- or tri-alkylsubstituted phosphoric acids or phosphonic acids; derivatives (e.g.,esters, amides, metal salts and the like) of mono-, di- or tri-alkylsubstituted phosphoric acids or phosphonic acids; mono-, di- ortri-alkyl substituted amines; mono- or di-alkyl substituted amides andcombinations thereof. In some embodiments examples of friction modifiersinclude, but are not limited to, alkoxylated fatty amines; borated fattyepoxides; fatty phosphites, fatty epoxides, fatty amines, boratedalkoxylated fatty amines, metal salts of fatty acids, fatty acid amides,glycerol esters, borated glycerol esters; and fatty imidazolines asdisclosed in U.S. Pat. No. 6,372,696, the contents of which areincorporated by reference herein; friction modifiers obtained from areaction product of a C₄ to C₇₆, or a C₆ to C₂₄, or a C₆ to C₂₀, fattyacid ester and a nitrogen-containing compound selected from the groupconsisting of ammonia, and an alkanolamine and the like and mixturesthereof. The amount of the friction modifier may vary from about 0.01wt. % to about 10 wt. %, from about 0.05 wt. % to about 5 wt. %, or fromabout 0.1 wt. % to about 3 wt. %, based on the total weight of thelubricating oil composition.

The lubricating oil composition of the disclosure can contain amolybdenum-containing friction modifier. The molybdenum-containingfriction modifier can be any one of the known molybdenum-containingfriction modifiers or the known molybdenum-containing friction modifiercompositions.

Preferred molybdenum-containing friction modifier is, for example,sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenumdithiophosphate, amine-molybdenum complex compound, oxymolybdenumdiethylate amide, and oxymolybdenum monoglyceride. Most preferred is amolybdenum dithiocarbamate friction modifier.

The lubricating oil composition of the invention generally contains themolybdenum-containing friction modifier in an amount of 0.01 to 0.15 wt.% in terms of the molybdenum content.

The lubricating oil composition of the invention preferably contains anorganic oxidation inhibitor in an amount of 0.01-5 wt. %, preferably0.1-3 wt. %. The oxidation inhibitor can be a hindered phenol oxidationinhibitor or a diarylamine oxidation inhibitor. The diarylamineoxidation inhibitor is advantageous in giving a base number originatingfrom the nitrogen atoms. The hindered phenol oxidation inhibitor isadvantageous in producing no NOx gas.

Examples of the hindered phenol oxidation inhibitors include2,6-di-t-butyl-p-cresol, 4,4′-methylenebis(2,6-di-t-butylphenol),4,4′-methylenebis(6-t-butyl-o-cresol),4,4′-isopropylidenebis(2,6-di-t-butylphenol),4,4′-bis(2,6-di-t-butylphenol),2,2′-methylenebis(4-methyl-6-t-butylphenol),4,4′-thiobis(2-methyl-6-t-butylphenol),2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],octyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octadecyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and octyl3-(3,54-butyl-4-hydroxy-3-methylphenyl)propionate, and commercialproducts such as, but not limited to, Irganox L135® (BASF), Naugalube531® (Chemtura), and Ethanox 376® (SI Group).

Examples of the diarylamine oxidation inhibitors includealkyldiphenylamine having a mixture of alkyl groups of 3 to 9 carbonatoms, p,p-dioctyldiphenylamine, phenyl-naphthylamine,phenyl-naphthylamine, alkylated-naphthylamine, and alkylatedphenyl-naphthylamine. The diarylamine oxidation inhibitors can have from1 to 3 alkyl groups.

Each of the hindered phenol oxidation inhibitor and diarylamineoxidation inhibitor can be employed alone or in combination. If desired,other oil soluble oxidation inhibitors can be employed in combinationwith the above-mentioned oxidation inhibitor(s).

The lubricating oil composition of the invention may further contain anoxymolybdenum complex of succinimide, particularly a sulfur-containingoxymolybdenum complex of succinimide. The sulfur-containingoxymolybdenum complex of succinimide can provide increased oxidationinhibition when it is employed in combination with the above-mentionedphenolic or amine oxidation inhibitors.

In the preparation of lubricating oil formulations, it is commonpractice to introduce the additives in the form of 10 to 80 wt. % activeingredient concentrates in hydrocarbon oil, e.g. mineral lubricatingoil, or other suitable solvent.

Usually these concentrates may be diluted with 3 to 100, e.g., 5 to 40,parts by weight of lubricating oil per part by weight of the additivepackage in forming finished lubricants, e.g. crankcase motor oils. Thepurpose of concentrates, of course, is to make the handling of thevarious materials less difficult and awkward as well as to facilitatesolution or dispersion in the final blend.

Processes of Preparing Lubricating Oil Compositions

The lubricating oil compositions disclosed herein can be prepared by anymethod known to a person of ordinary skill in the art for makinglubricating oils. In some embodiments, the base oil can be blended ormixed with the metal or metalloid hydrogen atom donor compoundsdescribed herein. Optionally, one or more other additives in additionalto the metal or metalloid hydrogen atom donor compounds can be added.The metal or metalloid hydrogen atom donor compounds and the optionaladditives may be added to the base oil individually or simultaneously.In some embodiments, the metal or metalloid hydrogen atom donorcompounds and the optional additives are added to the base oilindividually in one or more additions and the additions may be in anyorder. In other embodiments, the metal or metalloid hydrogen atom donorcompounds and the additives are added to the base oil simultaneously,optionally in the form of an additive concentrate. In some embodiments,the solubilizing of the metal or metalloid hydrogen atom donor compoundsor any solid additives in the base oil may be assisted by heating themixture to a temperature from about 25° C. to about 200° C., from about50° C. to about 150° C. or from about 75° C. to about 125° C.

Any mixing or dispersing equipment known to a person of ordinary skillin the art may be used for blending, mixing or solubilizing theingredients. The blending, mixing or solubilizing may be carried outwith a blender, an agitator, a disperser, a mixer (e.g., planetarymixers and double planetary mixers), a homogenizer (e.g., Gaulinhomogenizers and Rannie homogenizers), a mill (e.g., colloid mill, ballmill and sand mill) or any other mixing or dispersing equipment known inthe art.

Application of the Lubricating Oil Compositions

The lubricating oil composition disclosed herein may be suitable for useas motor oils (that is, engine oils or crankcase oils), in aspark-ignited internal combustion engine, particularly a directinjected, boosted, engine that is susceptible to low speed pre-ignition.

The following examples are presented to exemplify embodiments of theinvention but are not intended to limit the invention to the specificembodiments set forth. Unless indicated to the contrary, all parts andpercentages are by weight. All numerical values are approximate. Whennumerical ranges are given, it should be understood that embodimentsoutside the stated ranges may still fall within the scope of theinvention. Specific details described in each example should not beconstrued as necessary features of the invention.

EXAMPLES

The following examples are intended for illustrative purposes only anddo not limit in any way the scope of the present invention.

The test compounds were blended in lube oil and their capacity forreducing LSPI events were determined using the test method describedbelow.

Low Speed Pre-ignition events were measured in a Ford 2.0 L Ecoboostengine. This engine is a turbocharged gasoline direct injection (GDI)engine. The Ford Ecoboost engine is operated in four-roughly 4 houriterations. The engine is operated at 1750 rpm and 1.7 MPa break meaneffective pressure (BMEP) with an oil sump temperature of 95° C. Theengine is run for 175,000 combustion cycles in each stage, and LSPIevents are counted.

LSPI events are determined by monitoring peak cylinder pressure (PP) andthe crank angle of 2% mass fraction burn (MFB02) of the fuel charge inthe cylinder. When both criteria are met, it can be said that an LSPIevent has occurred. The threshold for peak cylinder pressure varies bytest, but is typically 4-5 standard deviations above the averagecylinder pressure. Likewise, the MFB02 threshold is typically 4-5standard deviations earlier than the average MFB02 (represented in crankangle degrees). LSPI events can be reported as average events per test,events per 100,000 combustion cycles, events per cycle, and/orcombustion cycles per event. The results for this test is shown below.

An additive associated with a test lubricant that reduces the LSPIfrequency, when compared to the corresponding baseline lubricant, isconsidered an additive that mitigates LSPI frequency. The test resultsare set forth in Table 1.

Baseline Formulation

The base line formulation contained a Group 2 base oil, a mixture ofprimary and secondary dialkyl zinc dithiophosphates in an amount toprovide 737-814 ppm phosphorus to the lubricating oil composition, amixture of polyisobutenyl succinimide dispersants (borated and ethylenecarbonate post-treated), a molybdenum succinimide complex, an alkylateddiphenylamine antioxidant, a borated friction modifier, a foaminhibitor, a pour point depressant, and an olefin copolymer viscosityindex improver.

The lubricating oil compositions were blended into a 5W-30 viscositygrade oil.

Metal or metalloid hydrogen atom donor Compound A (Triphenylsilane)

Triphenylsilane was commercially available from Millipore Sigma® orGelest®.

Metal or metalloid hydrogen atom donor Compound B (Tributylgermane)

Tributylgermane was commercially available from Millipore Sigma®.

Example 1

A lubricating oil composition was prepared by adding 458 ppm of siliconfrom the triphenylsilane and 2164 ppm of calcium from a combination ofoverbased Ca sulfonate and phenate detergents to the baselineformulation.

Comparative Example 1

A lubricating oil composition was prepared by adding 2255 ppm of calciumfrom a combination of overbased Ca sulfonate and phenate detergents tothe baseline formulation.

Example 2

A lubricating oil composition was prepared by adding 1483 ppm ofgermanium from the tributylgermane and 2204 ppm of calcium from acombination of overbased Ca sulfonate and phenate detergents to thebaseline formulation.

TABLE 1 LSPI Test Results in Ford LSPI Test % % Reduc- Reduc- tion tionin LSPI in LSPI Comp. activity Ex. activity Ex. 1 Ex. 1 Ex 1 2 Ex 2 Si(ppm) from 454 0 NA 0 NA compound A Ca (ppm) 2164 2255 NA 2204 NA Ge(ppm) from 0 0 NA 1483 NA compound B Average Events 8.5 19.25 56% 10 48%Average Events > 90 bar 3.25 13.25 75% 5.75 56% Average Events > 100 bar1.75 10.75 84% 5 53% Average Events > 110 bar 1.75 9.0 81% 4.25 52%Average Events > 120 bar 1.75 8.25 79% 4 51% *Counts all cycles of LSPIwhere both MFB02 and Peak Pressure Requirements are met.

The data shows that Applicant's inventive examples comprising a metal ormetalloid hydrogen atom donor compound of the disclosure providedsignificantly better LSPI performance both in terms of number of eventsand also the number of severe LSPI events than the comparative exampleswhich did not contain the metal or metalloid hydrogen atom donor in theFord engines. Severity is reduced by decreasing the number of highpressure events (i.e. over 120 bar) that can damage an engine.

What is claimed is:
 1. A lubricating oil composition comprising a metalor metalloid hydrogen atom donor compound selected from the groupconsisting of silicon hydrides, germanium hydrides, and tin hydrides. 2.The lubricating oil of claim 1, wherein the metal or metalloid hydrogenatom donor compound has the following formula:

wherein R₁, R₂, and R₃ are each independently selected from hydrogenatom, a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R,₁, R₂, and R₃ are a hydrogen atom; R₄is a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, ora C3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and M is asilicon atom, germanium atom, or tin atom.
 3. The lubricating oil ofclaim 2, wherein the metal or metalloid hydrogen atom donor compound hasthe following formula:

wherein R₂ and R₃ are each independently selected from a C6-C14 arylgroup, alkyl group, or a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆,—O(═O)R₇, or chlorine atom, R₄ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₅ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₆ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₇ is aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group; and M is a silicon atom, germanium atom, or tinatom.
 4. The lubricating oil of claim 2, wherein the metal or metalloidhydrogen atom donor compound has the following formula:

wherein R₁, R₂, and R₃ are each independently selected from hydrogenatom, a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₁, R₂, and R₃ are a hydrogen atom; R₄ isa C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.
 5. Thelubricating oil of claim 4, wherein the metal or metalloid hydrogen atomdonor compound has the following formula:

wherein where R₂ and R₃ are each independently selected from hydrogenatom, a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,R₄ is a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,or a C3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.
 6. Thelubricating oil composition of claim 2, wherein the metal or metalloidhydrogen atom donor compound has the following formula:

wherein R₁, R₂, and R₃ are each independently selected from hydrogenatom, a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₁, R₂, and R₃ are a hydrogen atom; R₄ isa C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.
 7. Thelubricating oil composition of claim 2, wherein the metal or metalloidhydrogen atom donor compound has the following formula:

wherein R₁, R₂, and R₃ are each independently selected from hydrogenatom, a C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group,a C3-C10 cycloalkyl group, —(OR₄), —NR₅R₆, —O(═O)R₇, or chlorine atom,such that not more than one of R₁, R₂, and R₃ are a hydrogen atom; R₄ isa C6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, R₅ is H, a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R₆ is H, aC6-C14 aryl group, saturated or unsaturated C1-C30 alkyl group, or aC3-C10 cycloalkyl group, and R₇ is a C6-C14 aryl group, saturated orunsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.
 8. Thelubricating oil composition of claim 1, wherein the metal or metalloidhydrogen atom donor compound has the following formula:

wherein is R₈ is a C6-C14 aryl group, saturated or unsaturated C1-C30alkyl group, or a C3-C10 cycloalkyl group; and n is 0 or an integer from1 to
 400. 9. The lubricating oil composition of claim 1, wherein themetal or metalloid hydrogen atom donor compound has the followingformula:

wherein n is 0 or an integer from 1 to
 400. 10. The lubricating oilcomposition of claim 1, wherein the metal or metalloid hydrogen atomdonor compound has the following formula:

wherein R₉ is a C6-C14 aryl group, saturated or unsaturated C1-C30 alkylgroup; and m is an integer from 1 to
 20. 11. The lubricating oilcomposition of claim 1, wherein the composition further comprises adetergent selected from calcium detergents, magnesium detergents, sodiumdetergents, lithium detergents, and potassium detergents.
 12. Thelubricating oil composition of claim 11, wherein the detergent is acarboxylate, salicylate, phenate, or sulfonate detergent.
 13. Thelubricating oil composition of claim 1, wherein the composition furthercomprises a molybdenum containing compound.
 14. The lubricating oilcomposition of claim 1, wherein the composition further comprises atleast one other additive selected from an ashless dispersant, an ashlessantioxidant, a phosphorus- containing anti-wear additive, a frictionmodifier, and a polymeric viscosity modifier.
 15. A method forpreventing or reducing low speed pre-ignition in a direct injected,boosted, spark ignited internal combustion engine, said methodcomprising the step of lubricating the crankcase of the engine with alubricating oil composition comprising from about 25 to about 3000 ppmof metal from at least one metal or metalloid hydrogen atom donorcompound selected from the group consisting of silicon hydrides,germanium hydrides, and tin hydrides, based on the total weight of thelubricating oil composition.
 16. Use of at least one metal or metalloidhydrogen atom donor compound selected from the group consisting ofsilicon hydrides, germanium hydrides, and tin hydrides in a lubricatingengine oil composition for preventing or reducing low speed pre-ignitionin a direct injected, boosted, spark ignited internal combustion engine.17. The use according to claim 16, wherein the at least one metal ormetalloid hydrogen atom donor compound is present at from about 25 toabout 3000 ppm of metal from the metal hydride, based on the totalweight of the lubricating oil composition.
 18. The use according toclaim 16 wherein the engine is a down-sized boosted engine ranging from0.5 liters to 3.6 liters.